1. Field of the Invention
The present invention relates to frame-merging technology, more particularly to a frame-merging apparatus and method suitable for real-time applications.
2. Description of the Related Art
In response to increasing demand for real-time applications of wireless networks, IEEE (Institute of Electrical and Electronics Engineers) 802.11n recommends provision of a transmission rate as high as 600 Mbps (Megabits per second). However, while most transmission content for real-time applications includes frames of a small size, for the purpose of transmission and reception identification, regardless of how small the volume of effective data of a frame is, overhead must be attached for transmission. This not only causes waste of channel bandwidth, but also limits the degree to which throughput may be increased.
As a result, the prior art proposes three types of frame-merging schemes that perform transmission after a plurality of frames are merged, thereby increasing throughput. These frame-merging schemes include A-MSDU (Aggregated Media Access Control Service Data Unit), A-MPDU (Aggregated Media Access Control Protocol Data Unit), and A-PPDU (Aggregated Physical Packet Data Unit). However, each scheme is suitable for a particular channel having a different transmission quality and transmission characteristics due to the unique merging method employed thereby. For instance, the overhead of A-MSDU is such that if one of the MSDUs is damaged, all the MSDUs must be re-transmitted due to the fact that many MSDUs are directed to the same destination. As a result, A-MSDU is more suitable for use in ideal channels. Moreover, A-MSDU uses a lower overhead than the other two frame-merging schemes, and therefore, A-MSDU is able to exhibit a higher channel efficiency and throughput in ideal channels.
It is evident from the above that with respect to a communication system that needs to deal with channel fluctuations, it is not possible to achieve an improvement in throughput using merely a single frame-merging scheme.